The present invention relates to a photographic processing unit for photographic photosensitive material, such as an exposed photographic film and exposed photographic printing paper, and particularly relates to a photographic processing unit suitable for a compact automatic photographic processing apparatus.
In professional and amateur photographic processing places, hospitals, clinics and so forth, an exposed black and white photographic photosensitive material, such as a black and white photographic film, black and white photographic printing paper and an X-ray film, is conventionally developed in a constant-temperature vessel by an operating person in a darkroom while the developed image on the material is inspected by his naked eyes. For such manual development, the operator must control the period of time of the development based on his hunch and also must control the temperature of the developing and the fixing solutions for the material based on his hunch, while looking at a thermometer. For that reason, he cannot always carry out the development operation under optimal conditions, and an unskilled person cannot properly perform the development operation. This is a problem. Additionally, the darkroom occupies a considerably large amount of space. This is another problem. Since it is dark in the darkroom, it is not easy to perform the development operation. This is yet another problem. If a dentist enters into the darkroom to develop every single exposed dental X-ray film, the efficiency of his work is greatly deteriorated. This is a big problem.
In order to solve the above problems, a roller-type automatic developing apparatus, as shown in FIG. 6, for performing development in a darkroom was proposed and has been put into practical use. The developing tank 2 of the apparatus 1 is divided into at least four sections, including a developing chamber 3, a fixing chamber 4, a rinsing chamber 5 and a drying chamber 6. Since a developing solution 8, a fixing solution 9 and rinsing water 10 are simply contained in the developing chamber 3, the fixing chamber 4 and the rinsing chamber 5, respectively, an exposed photographic film 11 needs to be moved carefully in a zigzag vertical path, as shown in FIG. 6, so as to be dipped in the processing liquids in the respective chambers, as the film is conveyed. For that reason, some film conveyance rollers 12 are within the developing and the fixing solutions 8 and 9, thereby likely causing the rollers to become contaminated or damaged. This is a problem. Since as many as forty-eight film conveyance rollers 12 are provided to convey the film 11, the length of the apparatus 1 is so large that it cannot be made compact. This is another problem. Since the film conveyance rollers 12 are moved down by a prescribed distance so as to be dipped in the developing and the fixing solutions 8 and 9 and the rinsing water 10, the line of the rollers meanders up and down so that the film 11 being conveyed by the rollers is moved in zigzag fashion. For that reason, the film 11 repeatedly undergoes bending, and is therefore likely to be damaged. This is yet another problem. Since the film conveyance rollers 12 are likely to become contaminated, they will not rotate smoothly, and the development of the film 11 is likely to be nonuniform. This is yet another problem.
Photographic processing apparatus each for processing a photographic photosensitive material while moving it in a horizontal direction is disclosed in German Patent No. 1,293,586 and U.S. Pat. No. 4,577,949. Each such apparatus includes upper and lower processing liquid chambers divided from each other so that a processing chamber is defined between the processing liquid chambers. Conveyance rollers are provided at the front and rear of the processing liquid chambers. The photosensitive material is conveyed in the horizontal direction through the processing chamber as the material is moved between the conveyance rollers. At that time, a processing liquid is supplied from the upper and the lower processing liquid chambers to the processing chamber to process the material. However, the constitution of the processing liquid chambers is complicated. This is a problem. In particular, the constitution of the processing liquid chambers of the apparatus disclosed in the United States Patent is very complicated because of the presence of a comb-like member provided in a liquid passage in the processing chamber in order to improve the uniformity of the processing liquid therein. Also, the conveyance rollers are present in the processing liquid or retain the liquid, so that the rollers are contaminated, causing them to rotate erratically and result in nonuniform development of the material. This is another problem.